Validate email address using REGEX

validate_email_address.js

var $email = $('form input[name="email'); //change form to id or containment selector
var re = /[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}/igm;
if ($email.val() == '' || !re.test($email.val()))
{
    alert('Please enter a valid email address.');
    return false;
}